/Engine/Source/Runtime/Engine/Classes/Engine/AssetManager.h
Returns the loading handle associated with the primary asset, it can then be checked for progress or waited on
Streamable Handle that can be used to poll or wait
[TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FStreamableHandle](API\Runtime\Engine\Engine\FStreamableHandle) > GetPrimaryAssetHandle ( const [FPrimaryAssetId](API\Runtime\CoreUObject\UObject\FPrimaryAssetId) & PrimaryAssetId, bool bForceCurrent, [TArray](API\Runtime\Core\Containers\TArray)< [FName](API\Runtime\Core\UObject\FName) > * Bundles ) const